This year marks the creation of a cent struck in aluminum to replace copper whose price was rising to the point where a penny was worth more than one cent.

Over 1.5 million of these aluminum cents J2151/P2084 were produced but ultimately they were not released. Because of the number produced, many consider these to be a rejected regular issue, like the 1964 Peace dollar as opposed to being a true pattern.

The mint also produced trial pieces in bronze-clad steel J2152.

It is believed that several of both of these are in collectors hands but are not legal to own.

Photo courtesy of the National Numismatic Collection of the Smithsonian Institution.